The botanical family known as Labiatae is commonly referred to as the mint family. Labiatae herbs include such genera as Salvia (sage), Rosmarinus (rosemary), Mentha (mint), Ocimum (basil), Thymus (thyme), Marrubium (hoarhound), Monarda (horse-mint), Trichostema (bluecurls), Teucrium, Hyptis, Physostegia, Lamium (henbit), Stachys, Scutellaria (skullcap), Nepeta (catmint). Members of the Verbenaceae family include Lippia (Mexican Oregano) and Lycopus. 
Labiatae herbs are well known for the aromatic volatile or essential oils in their foliage, which oils are used in perfumes, flavorings, and medicines. Among the more important essential oils are those derived from sage, lavender, rosemary, patchouli, and the true mints. Members of the Labiatae family have been used for medicinal purposes, for example catnip, pennyroyal, hyssop, bee balm, yerba Buena and the true mints.
Typically, medicaments derived from members of family Labiatae utilize oil extracts from plants. In particular, antimicrobial compositions can be formulated by combining extracts of an essential oil with an organic acid or a Group I salt. It is believed that antimicrobial activity may be attributed to the presence of organic phenolic compounds, such as isopropyl-o-cresol, (5-isopropyl-2-methylphenol) and/or isopropyl-cresol (5-methyl-2[1-methylethyl]phenol) in the oil extract from the plants.
The natural compound menthol (essential oil alcohol) can be purified from the essential volatile oils of members of the Mentha genus. Menthol (1-Methyl-4-isopropyl cyclohexane-3-ol, or hexahydrothymol) is used in numerous products for its pleasing taste, aroma, and pharmacological properties. Menthol is known to have significant antibacterial activities and has been used in herbal treatments to cure internal and external infections.
Labiatae plants contain two other chemical compounds in their volatile oils which are known to possess antimicrobial activities. These are commonly referred to as carvacrol (5-isopropyl-2-methylphenol or isopropyl-o-cresol) and thymol (5-methyl-2[1-methylethyl]phenol or isopropyl-cresol). Both substances are monoterpene phenolic compounds and are potent antimicrobial agents. Typically, carvacrol and thymol can be synthetic or obtained from the oil extract of Labiatae plants.
Labaiate plants contain a number of phenolic compounds, such as eriocitrin, luteuolin-7 rutinoside, hesperoside, rosmarinic acid. (Duban F. et al., (1992) “Aromatic and polyphenolic composition of infused peppermint, Mentha x. piperita L.” Ann. Pharm. Fr. 50(3):146-55). The polyphenols are known to demonstrate antioxidant activity and are predominantly found in the aqueous or organic extracts of Labiatae plants.
Cells of Mentha plants are also known to contain a number of water-soluble polysaccharides, primary pectins, identified as (1-->3)-linked galactan carrying arabinosyl residues on C-6 and (1-->4)-alpha-linked galacturonan partially interspersed with (1-->2)-linked rhamnosyl residues (Maruyama K, et al., (1998) “Pectins in extracellular polysaccharides from a cell-suspension culture of Mentha”; Biosci Biotechnol Biochem. 62(11):2223-5). Other polysaccharide constituents are xyloglucans, containing xylose, glucose, arabinose, galactose, mannose and fucose residues. (Maruvama K, et al., (1996) “O-acetylated xyloglucan in extracellular polysaccharides from cell-suspension cultures of Mentha.” Phytochemistry 41(5): 1309-14).
Plants of the Labiatae family are highly valued for their essential oils. Components derived from the plant material, other than the essential oils, are also desired. Methods for isolating water soluble components from Labiatae plant materials are disclosed in U.S. Pat. No. 5,908,650 to Lenoble, et al. Lenoble, et al. describe a process of preparing a water-soluble rosemary extract by extracting rosemary leaves into water and acidifying the extract. The acidified crude extract is then loaded onto a reversed-phase media to remove undesirable components (e.g., polysaccharides, salts, and insoluble compounds). The desired fraction is then washed off the column. The isolated product contains a significant amount of flavonoid glucuronides and glycosides in addition to the antioxidant rosmarinic acid. Furthermore, the material isolated by the Lenoble, et al. method contains too much flavor and color to be suitable in certain applications.
A method of producing an improved water-soluble plant extract of one or more antioxidant compounds from Labiatae plant material is disclosed in Bailey, et al. (U.S. Published Patent Application No. 2003/0138537). The process disclosed in Bailey, et al. generally includes hot water extraction of the plant biomass for several hours, followed by acidification of the water extract and extraction of the antioxidant compounds into a water-immiscible organic solvent. Bailey, et al. describe an improved purification scheme for antioxidant compounds from Labiatae family plant material and is selective for the purification of antioxidants through acidification. Bailey, et al. discuss that a higher percentage of the desired antioxidant compound could be isolated by converting it to the protonated at low pH (below pKi) form and resulting in a higher percentage which is recovered in the water-immiscible organic solvent. The extract may be further processed to remove remaining trace amounts of compounds responsible for the taste, odor, and/or color which may be undesirable in certain commercial applications.
Commercial applications for Labiatae family plant extracts include the flavoring agents, flavor stabilizers, pigment stabilizing agents and antimicrobial agents. Labiatae-derived essential oils are used in dental care preparations primarily as flavoring agents and for the antimicrobial benefits afforded from the carvacrol and thymol components in the oils. As the Labiatae essential oils often impart strong organoleptic characteristics, it is desired to provide a composition for oral care which does not impart unwanted flavors in the oral care composition.
The aims of oral care are to prevent and/or treat dental diseases as well as provide cosmetic benefits.
Dental caries is an oral disease caused by bacterial pathogens and it affects hundreds of millions of people worldwide. The primary pathogens responsible for colonizing the oral cavity are the bacteria Streptococcus mutans and Streptococcus sorbinus. 
Caries are understood to result from the accumulation of plaque on the teeth and production of organic acids (plaque acids) when plaque bacteria ferment sugars and starches in food residue left behind in the oral cavity. Before being washed away by saliva, the acids accumulate in the plaque long enough to lower the pH and to cause some of the enamel, a calcium-phosphorous mineral known as hydroxyapatite, to dissolve, that is, demineralize, which can lead to dental caries (tooth decay), and tooth sensitivity. Thus, the reversed process, re-mineralization, is an extremely important objective in the fields of preventive and restorative dentistry.
Another factor of cariogenesis is the accumulation of plaque bacteria which extracellularly produce glucosyltransferase (GTF) enzymes, which enzymes catalyze formation of glucans from sucrose. These glucans cover tooth surfaces and serve as the backbone of dental plaque. Plaque formation also involves the participation of a number of other opportunistic bacteria which are capable of attaching to the glucans and colonizing the tooth surface.
Glucosyltransferases are expressed and secreted by oral pathogens such as Streptococcus mutans and Streptococcus sobrinus. The GTF enzymes share a high degree of homology, and consist of two functional domains—catalytic and glucan binding, (Monchois V. et al, (1999) “Glucansucrases: mechanism of action and structure-function relationships” FEMS Microbiology Reviews 23:131-151). It is known that some low molecular weight inhibitors of GTF, such as 6-deoxysucrose, act through interfering with the catalytic domain of GTF. It is known that oligosaccharides or polysaccarides other than glucans can bind GTF and act as acceptors. To inhibit GTF activity, it may be desirable to obtain oligosaccharides or polysaccharides which are capable of binding with GTF, but are not able to serve as an acceptor for nascent glucan synthesis in plaque formation. Consequently, oral care preparations comprising such polysaccharides may be effective for preventing or reducing cariogenesis.
A method of preventing the formation or aggravation of dental plaque by inhibition of GTF activity is disclosed in U.S. Pat. No. 5,204,089 to Hara, et al. Inhibition of GTF activity is demonstrated with selected polyphenols derived from tea.
Inhibition of GTF activity by polyphenol compounds derived from the fruits of the Rosaceae family is disclosed in U.S. Pat. No. 5,853,728 to Tanabe, et al. The polyphenol derived from the fruits of Rosaceae family belongs to a group of plants having the highest free radical erasing activity among those reported for vegetable extracts evaluated. The polyphenol derived from the fruits of Rosaceae contains simple polyphenol compounds including caffeic acid derivatives, p-coumaric acid derivatives, flavan-3-ols, flavonols, dihydrochalcones, and condensed tannins. Polyphenols are disclosed to hinder the activity of glucosyltransferase produced by oral Streptococcus, specifically inhibiting the formation of deposit which is an important factor of dental caries. (Japanese Patent Application Laid-open No. 285876/1995). The disclosed function of the polyphenols also include antiallergic activity, ultraviolet light absorbing activity and free radical erasing activity for skin cosmetic material, and anticariogenic activity and deodorant activity for toothpaste.
Thus, a strategy for managing oral infections, besides mechanical removal of the formed plaque, may be based on application of antimicrobial agents, agents capable of inhibition of GTF, or their combination.
While there are a number of synthetic compounds on the market with anti-calculus properties, it is preferable that these agents be classified as “natural”, or even more preferably, as “Generally Recognized as Safe” (GRAS). Various pharmaceuticals for inhibiting cariogenesis have been proposed; however, there is still a strong demand toward developing a pharmaceutical preparation which is unlikely to cause harmful side effects to the human body because it is derived from naturally occurring sources.
Associated with dental disease may be some form of inflammation at the tooth/gum interface. Inflammation or the inflammatory process is a natural result of an insult to soft tissue, usually resulting in vascular, cellulovascular and/or tissue fibrosis. Such physiological manifestation of inflammation has been attributed to the release of cytokines and other messengers such as serotonin, prostaglandins, bradykinin, leukotrienes, histamine, and substance P.
Inhibition of prostaglandin production is a mechanism which has been exploited in the treatment of inflammation. Typical inhibitors of prostaglandins include non-steroidal anti-inflammatory drugs (NSAIDs); however, these substances are not without side effects. NSAIDs are known to inhibit prostaglandin production by inhibiting enzymes in the arachidonic acid/prostaglandin pathway including, particularly, cyclooxygenase (COX). Recently, research has identified a cylcooxygenase subtype, COX-2, inhibition of which is highly effective in inhibiting inflammatory processes and which inhibition results in minimal untoward side effects. So-called COX-2 inhibition is therefore a popular target for treating/preventing inflammation, including inflammation associated with dental disease.